Wednesday, 19 August 2015

Tubes

As you know, in the middle of last week I ordered the metal that I intend to use as the basis for the tube bundle thrust chamber.The 316L tube and hollow bar arrived today. The hollow bar came from Schoeller Bleckmann in Oldbury and the tube from Steel Express in Wolverhampton. I also ordered a piece of 316L plate. This didn't arrive today so I will have to chase it up tomorrow.The hollow bar is 212mm OD x 170mm ID. Here is a photograph of it sitting in it's protective sack. It was too heavy to lift out...

This has to go in the lathe somehow. My current thinking is to drill and tap the piece and then bolt it directly to the faceplate.Here is the 316L tube, it is 10mm OD x 2mm wall:-

These tubes will need to be cut into near enough identical lengths. I have decided to make a cutting jig based around an angle grinder to do this.The jig will be composed of a section of aluminium angle welded to an aluminium plate. This angle will act as a sort of V block to hold the tube being cut. Sections of drilled and tapped aluminium flat bar will be welded on to the angle to form a clamping feature. The angle grinder will then be mounted on a pivoted bracket, enabling repeatable cut off to be achieved.Here is the base plate of the jig:-

This picture shows the angle with a piece of flat bar showing how this will be mounted to form a clamp:-

I milled the flat bar sections square - not strictly necessary but it made me feel better:-

Here is a final shot of the angle and plate trialled up with a scrap piece of angle to show the position of the angle grinder bracket:-

I will also have to make a tube bending jig, so there will be plenty of practical updates over the next few weeks. Once the jigs are made, I can trial the actual tube fabrication process.Keep watching.

Thank you very much for commenting David. I thought about buying a chop saw, but I have the time and the inclination...so just thought I'd make one. That said I will look into the tool you suggest, thanks again.

About this blog

This blog describes the research, design and construction of a Liquid Rocket Engine.
As such it will include information regarding the design and construction of rocket engine components.
This will encompass theoretical and performance concerns, as well as machining, welding and manufacturing techniques used to overcome the various problems encountered.
In addition, my interests in this direction include control and data acquisition. So there will be posts regarding electronic systems and microcontrollers.
It is my hope that as well as being of interest to the rocket engine community, it should also become a repository of general amateur engineering information.
I was inspired to create a blog by the groundswell of interest that I have had in my project from people I have met. I have found that their reactions tend to go from perplexity to enthusiasm rapidly! The main question most people have is not to do with the technical obstacle to be overcome. Most of those who have asked me about my project have wanted to know "Why are you doing this?" So I will try to give some answers to this and to explore my motivation to think, research, create and construct.